The stimulation of muscles in the human body by way of electrical stimuli to provide involuntary muscular response has become a useful remedial, diagnostic, and clinical technique. One example where electrical stimuli are used to provide involuntary muscular response relates to masticatory and facial muscles. In particular, the muscles that directly relate to the mandibular closure.
Generally, instead of stimulating the actual muscles associated with the mandibular closure, nerves associated with the mandibular and facial muscles are stimulated to attempt to achieve remedial, diagnostic, and clinical results. This is because direct stimulation of the muscles is impractical due to the number of electrodes that would be required to stimulate these muscles. Moreover, electrical stimulation of nerve fibers associated with masticatory and facial muscles helps to ensure stimulation of the entire muscle complex associated with the mandible. Furthermore, six to eight times less electrical energy is required to effectively stimulate the motor nerves than would be required for direct muscle stimulation of the masticatory and facial muscles.
Use of electrical stimulation of the motor nerves controlling the masticatory and facial muscles allows for near balanced closure of the mandible. If simultaneous and bilateral stimulation of the masticatory and facial muscles can be achieved, a number of clinical and diagnostic techniques are possible. For example, controlled stimulation may be employed to diagnose the comparative degree of relaxation or contracture of the muscle groups on each side of the face, to cause the mandible to close to the horizontal myocentric position of the occlusion, to determine the vertical position of occlusion, to make denture impressions, to relax muscle spasms associated with temporomandibular joint syndrome (TMJ), and to reduce post-operative swelling and discoloration by causing gentle massage as the muscles contract.
Furthermore, since pain and spasm associated with mandibular and facial muscles can be referred to shoulder and back muscles, the relaxation and therapy of shoulder and back muscles are of particular importance. To accomplish desired results requires a versatile apparatus adapted to provide amplitude pulses to the nerve fibers that control the masticatory, back and shoulder, and facial muscles. Generally, these amplitude pulses are provided by way of electrical stimulus of particular quantity and duration that provides for near optimum stimulation of the muscles without undue fatigue. For example, an intermittent or a pulsing current having a duration of about half (½) a millisecond and the frequency of about 40 pulses per minute may be used to stimulate the nerves associated with the muscles.
It has been found that the current electrical stimulation devices provide somewhat satisfactory results associated with the masticatory and facial muscles. However, improvements may be made in current techniques used to stimulate the masticatory and facial muscles.